(I won't put a screenshot here ,because I'm lazy)
The games I've played the most are easily Team Fortress 2 (1800+ hours) , Killing Floor (257 hours) , Left 4 Dead 2 (almost 200) , Dawn of War Soulstorm (210 hours,mostly because of mods) , Borderlands 2 (on xbox so I don't know) , Mortal Kombat 9 (same) , Age of Empires 2 and Burnout 3(when I was a child ,these were my favourite games) ,Binding of Isaac (with both the original and Rebirth, it cranks to almost 400 hours) and Awesomenauts (128 hours) . And of course my all-time favourite serie : MASS EFFECT (countless hours on xbox... I finished the games dozens of times . It's just perfect,and don't even launch a debate on the ending)
Honorable mentions to Terraria,Epic Battle Fantasy 4 , Saints Row 3 and 4 ,Beat Hazard and Torchlight 2 . Not because I played a whole lot of them but because I think they never gets old. I come back to them every so often and that's just amazing. Also , I think that Torchlight 2 and Epic Battle Fantasy 4 deserves WAY MORE LOVE , they are cheap as hell and play amazingly great. (Just finished an EBF4 playthrough and will soon start a new Terraria one with the 1.3 update!)